
Blue John Cavern
Blue John is Britain’s rarest mineral, first discovered at Castleton by the Romans almost 2000 years ago. They are the world’s only known deposits of this extremely rare and beautiful stone.
Visit the caverns and learn how they are formed in limestone strata, and how the limestone itself had once been formed by the deposits found on the sand beds of great oceans. You will also witness fossilised remains of marine animals.